deflateBR is an R package used to deflate nominal Brazilian Reais
using several popular price indexes.
The deflateBR’s main function, deflate, requires three arguments to
work: a numeric vector of nominal Reais (nominal_values); a Date
vector of corresponding dates (nominal_dates); and a reference month
in the MM/YYYY format (real_date), used to deflate the values. An
example:
# Load the package
library(deflateBR)
# Deflate January 2000 reais
deflate(nominal_values = 100, nominal_dates = as.Date("2000-01-01"), real_date = "01/2018")
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#> [1] 310.3893Behind the scenes, deflateBR requests data from
IPEADATA’s API on one these five
Brazilian price indexes:
IPCA
and
INPC,
maintained by IBGE; and
IGP-M,
IGP-DI,
and
IPC
maintained by
FGV/IBRE.
To select one of the available price indexes, just provide one of the
following options to the index = argument: ipca, igpm, igpdi,
ipc, and inpc. In the following, the INPC index is used.
# Deflate January 2000 reais using the FGV/IBRE's INCP price index
deflate(100, as.Date("2000-01-01"), "01/2018", index = "inpc")
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#> [1] 318.1845With the same syntax, a vector of nominal Reais can also be deflated,
what is useful while working with data.frames:
# Create some data
df <- tibble::tibble(reais = seq(101, 200),
dates = seq.Date(from = as.Date("2001-01-01"), by = "month", length.out = 100)
)
# Reference date to deflate the nominal values
reference <- "01/2018"
# Deflate using IGP-DI
head(deflate(df$reais, df$dates, reference, "igpdi"))
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#> [1] 341.0412 342.7393 344.9315 345.5051 344.9379 346.6979For tidyverse users, the deflate function can be easily used inside
code chains:
library(tidyverse)
df %>%
mutate(deflated_reais = deflate(reais, dates, reference, "ipca"))
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#> # A tibble: 100 x 3
#> reais dates deflated_reais
#> <int> <date> <dbl>
#> 1 101 2001-01-01 296.
#> 2 102 2001-02-01 297.
#> 3 103 2001-03-01 299.
#> 4 104 2001-04-01 300.
#> 5 105 2001-05-01 301.
#> 6 106 2001-06-01 303.
#> 7 107 2001-07-01 304.
#> 8 108 2001-08-01 303.
#> 9 109 2001-09-01 304.
#> 10 110 2001-10-01 306.
#> # ... with 90 more rowsTo facilitate the task of deflating nominal Reais, the deflateBR
package also provides five convenience functions: ipca, inpc,
igpm, igpdi, and ipc. Each one of these functions deflate nominal
values using their corresponding price indexes. For instance, to deflate
nominal Reais using IGP-M, one can execute the following code:
igpm(100, as.Date("2000-01-01"), "01/2018")Or, using the IPCA index:
ipca(100, as.Date("2000-01-01"), "01/2018")In addition, the deflateBR package contains a function called
inflation that calculates the inflation rate between two dates
quickly. Providing initial and end dates in the MM/YYYY format, plus one
price index, the function returns the inflation rate in percent:
# Inflation rate between January and December of 2017
inflation("01/2017", "12/2017", "ipca")
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#> [1] 2.947421Install the latest released version from CRAN with:
install.packages("deflateBR")To install the development version of the package, use:
if (!require("devtools")) install.packages("devtools")
devtools::install_github("meirelesff/deflateBR")Following standard practice, seconded by the Brazilian Central
Bank,
the deflateBR adjusts for inflation by multiplying nominal Reais by
the ratio between the original and the reference price indexes. For
example, to adjust 100 reais of January 2018, with IPCA index of
4916.46, to August 2018, with IPCA of 5056.56 in the previous month, we
first calculate the ratio between the two indexes (e.g., 5056.56 /
4916.46 = 1.028496) and then multiply this value by 100 (e.g., 102.84
adjusted Reais). The deflate function gives exactly the same result:
deflate(100, as.Date("2018-01-01"), "08/2018", "ipca")
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#> [1] 102.8496To cite deflateBR in publications, please use:
citation('deflateBR')